Electrical circuit breaker



Patented May 2, 1939 UNITED STATES PATENT OFFICE 749,330, now Patent No. 2,080,178, dated May 11, 1937. Divided and this application April 26, 1937, Serial No.

8 Claims.

This invention relates to electrical circuit breakers and is aV division of my U. S. Letters Patent No. 2,080,178, issued May 11, 1937, and an object of this invention is to provide an improved means for opening an electric circuit while current is flowing therein and including a means for reducing the arcing at the terminals.

It has previously been the practice to provide a circuit breaker for the said purpose in which a liquid is used to enclose the terminals as for instance as disclosed in the U. S. patent to T. T. Greenwood, No. 1,825,228 or Herbert Pearce, Patent No. 1,841,147.

It is the present practice with circuit breakers to utilize insulating liquids or gases of high dielectric strength as the means for extinguishing or interrupting the arc. Such prior characters of interrupting devices are costly in character and large in size and introduce a re and explosion 2o hazard. The object of this invention is to avoid the use of such prior means and provide a circuit breaker differing materially from such prior art in that self-generated arc gases are of low dielectric strength and are utilized under high pressure to provide an extinguishing blast across the coacting surfaces of the arc terminals.

The invention distinguishes from previously known arc gas circuit breakers (such for instance as R. H. Read Patent No. 730,704) in that by means of a novel arrangement of the parts, the initially produced arc gases are passed through a restricted passageway of such form as to effect a partial deionization or cooling, cleaning and guiding of the gas blast.

It is further an object and feature of the invention to provide a circuit breaker which includes a series of contacts in such relation that the breaking of one produces a gas which is subsequently utilized to quench a second arc drawn in series with the iirst.

A further and major object of the invention resides in the provision of an intermediate contact element positioned between the main contacts of the circuit breaker wherein by iirst separating a main contact and the intermediate contact, an arc is drawn and thereafter the intermediate contact separated from the other main contact by pressure of gases produced by the rst arc which now under pressure between the said intermediate and second main contact.

These several objects and novel features of the invention are hereinafter more fully described and claimed, and an embodiment of the invention is shown in preferred form in the accompanying drawing in which- Fig. 1 is a longitudinal section of a convenient form of a circuit breaker embodying my invention.

Fig. 2 is a partial sectional View showing the contact elements in the position assumed upon the producing of the initial arc and the resultant gases.

Fig. 3 is a similar View showing the contacts fully open under a condition in which the gases rst produced are discharged to atmosphere.

Fig. 4 is a similar view showing an alternative form of intermediate contact element.

' Fig. 5 is a view of another convenient structural form of contact elements involving my invention.

Fig. 6 is an end view of a bushing supporting one of the terminals.

Fig. 7 showsan alternative arrangement of one of the main contact elements.

The preferred form of my improved circuit breaker as shown in Fig. 1, comprises a body II of insulating material. The speciic construction of this body may be'varied to suit different types of installation. The body has a bore II which opens through one end thereof and is closed by a threaded plug 20 with which is associated a packing means 20 of any desired character, preferably cementitious, between the plug and the body to seal the bore I IA at that end. Within the bore in the construction shown is a hollow movabl main electrode or contact member I2 attached at its outer end in any convenient manner to an operating rod I3 which is movable longitudinally of the axis of the Contact I2 by any approved means not here shown. The contact I2 has an external shoulder I2 which limits the withdrawal movement of the contact element as will be understood from Fig. 3 wherein, upon withdrawal to full extent, a shoulder engages the packing 20' or base of the plug through which the electrode extends. Within the contact I2 is the base of an intermediate Contact or electrode I 6 which has a tapered base 30 for contact with the correspondingly tapered end of the contact I2 as indicated in the Vposition of the parts shown in Fig. l. To this intermediate contact I6 is secured an insulating body l1, the outer free end of which is formed with a collar 2| somewhat greater in diameter than the body. This collar 2I is engaged by the internal shoulder 3| of the element I2 when it is withdrawn to the position shown in Fig. 2.

The intermediate electrode I6 has aV cone-like terminal portion 32 and as shown in Fig.1this coned end 32 engages the coneshaped end 33 o f Iii) 2 the hollow contact I4. This contact element I4 is mounted in a recess 34 in axial alignment with the chamber II and having a side outlet to atmosphere indicated at 35. The electrode or contact element I4 has an extension I9 with which one side 36 of the main circuit is connected while the other side 31 of the main circuit is connected to the contact I2 as diagrammatically shown in Fig. 1. There is a spring I5 engaging a base of the main contact i4 holding the same in the position shown, there being a slight movement of the contact I4 on the aXis of the intermediate member and the other main contact I2 to insure contact.

In this fundamental form of the invention, it will therefore be realized that there is a main contact I2, a companion main contact I4 and an intermediate contact I6 in engagement with both the said main contacts when in the closed position shown in Fig. 1. The intermediate contact I6 is pressed to engagement with the Contact I4 by means of a spring I8 in the hollow contact I2. Upon starting to open the circuit in this primary construction, the contact I2 is withdrawn by means of the operating rod I3 and associated instrumentalities (not here shown) for causing said movement.

Upon initiating movement of the contact I2, the tapered edge thereof is separated from the coned face 35 of the intermediate contact I6 which is in engagement with the main contact I 4. This causes an arc and development of a high pressure gas in the chamber II which, during this initial operation, remains closed. On further movement of the member I2 the shoulder 3| engages the enlarged portion 2l on the insulating member withdrawing the coned face 32 out of contact with the coned mouth 33 of the hollow contact I4. This permits the high pressure gas caused by the initial separation of the contacts I2 and I6 to pass through the narrow opening between the portion 32 of the intermediate contact I6 and the coned mouth 33 of the main electrode I4 to atmosphere through the passageways 34 and 35. The gas is partially deionized and cleaned by being forced against the wall of the bore or chamber I I and narrow passage between the intermediate `contact I6 and said wall. These gases are so guided as to pass over the surfaces of the intermediate electrode I6 and the main electrode I4 in intimate contact therewith and tend to quench the incipient arc between these members and maintain a steady high pressure blast over the arc terminals until the circuit is completely interrupted.

To insure separation of the contacts I6 and I4, the enlarged end portion 2I is provided for engagement with the shoulder 3l of the contact I2 whereby, prior to completion of movement of the operating rod in separating the contacts, the intermediate electrode or contact I6 is forcibly separated from the contact I4. In fact the intermediate contact may be provided with a longer insulation as indicated at II in Fig. 4 so that when the contact I2 reaches its limit of withdrawal movement, the enlarged portion 2| of the insulating element I'I will just be engaged by the shoulder 3I of the contact I2 whereby contact I6 remains in engagement with contact I4.

In the structure shown in Fig. 4, the final sepaaration of the intermediate contact I3 and main contact I4 is produced when the pressure within the chamber reaches a value suicient to move contact member I4 against the force of spring I5. In this latter case, as the pressure in the chamber decreases, the intermediate end I6 may again assume the position shown in Fig. 4 without closing the circuit as the said electrode is supported in the main electrode I2 by the insulation rod or element I'I.

It will be noted that, for the proper functioning of the device, the housing should be reasonably pressure tight except for the opening provided in the contact I4 and also that a narrow passageway should be provided between the member I6 and the inside wall of the housing for the purpose of maintaining the arcs in series and the deionizing and partial cleaning of the gases. The effectiveness of a gas blast for interrupting purposes is measured by the means found to produce a relatively smooth ow over the contact surfaces and through the arc core and in the case of arc gases, it is essential that the blast in the rst case should be relatively clear of metal particles and secondly, that the temperature should be appreciably lowered. In the structure embodying my invention these effects are accomplished in an inexpensive and simple manner. The restricted passageway serves to cool the gases and trap metal particles, while further the peripherically close association of the intermediate contact and the inside wall of the housing insures that the blast sweeps concentrically over the entire contact surfaces and longitudinally through the length of the arc core during the entire opening stroke of the circuit breaker. Also, for various applications, it is obvious that the insulation supporting the terminals may be carried in a metal casing.

In Fig. 5 there is shown an alternative form of construction of the intermediate contact element or electrode, it may have a body I I I formed with a central bore II2 and has a contact element I I3 corresponding in general to the element I2 of Fig. 1 and likewise movable in the bore I I2. In this construction, the bore II2 is enlarged at the right hand end as indicated at II4 and the outer end of the member III is threaded to receive a cap 4G. Between the cap and the end of the body is the packing material 40 which may be cementitious in character. The cap 40 has a flanged bushing or sleeve 39, the body of which extends into the bore II4. The hollow terminal I4 corresponds in all general respects to the terminal I4 of Fig. 1 and extends within the bushing 39 and has an enlarged inner end portion whichslidably ts in the bore of the sleeve 39. Between the body of the element I4 and the sleeve is located a spring I I 5 which tends to move the contact element I4 to the left to the position shown. The terminal end of the bushing or sleeve 39 is notched at 39 for a purpose hereinafter stated.

The intermediate contact or electrode IGI has a central ring like portion or flange 32, a coned forward end I33 for contacting the terminal I4, and a truncated cone shaped portion I 64 on the opposite side which is engaged by the coned edge IE5 of the movable terminal II3. This terminal Ii3, when moved to engagement with the coned face |54 of the intermediate electrode IBI, will force the electrode IBI and the Contact element I4 to the right until the ring like flange portion I62 engages the notched end of the sleeve 39. When in this position, upon movement of the element I I3 to the left, the intermediate electrode I6I will follow the same until the ange E62 thereof engages the shoulder between the bores II2 and II4 by inuence of the spring II5. As soon as this intermediate electrode III ceases to follow the movable electrode II3, the first arc is drawn and gas pressure developed in the bore II2 which Will force the electrode I6I and II4 to the right of the position shown until the flange |62 seats against the end of the sleeve 39. The gases may escape through the slots or notches 39 and the electrode I4, under this pressure, will move outwardly and the gases pass to atmosphere through the hollow portion thereof.

This form of the invention functions equally as well as the previously described forms and it is to be noted that, in this form of the invention, the spring II is practically shielded from direct contact with the heated gases.

In Fig. '7 is shown an alternative arrangement of the electrode I4 which in all essential respects is the same as that shown in Fig. l. The spring I5I, however, is positioned between a shoulder |52 in the interior of the body and the outturned end of the electrode I4 which receives the coned end of the electrode I6. A packing ring |53 is positioned behind the outturned end of the element I4 and practically fitting the bore II and the spring I5I lies in the recess between the packing and the shoulder |52 and thus is shielded from direct contact with the heated gases passing through the interior of the member I4 to atmosphere.

In either of the forms of the invention, the interruption of the arc is produced by the quenching effect of the gases developed in the central chamber of the insulating body and it is believed evident that the structure may be varied in detail in adapting the circuit breaker for various types of installation.

'I'he housing II of Fig. 1 or III of Fig. 5 may be of any desired construction or form and the material utilized in the contact supporting parts may be varied in respect to gas generating and arc resisting qualities, depending upon the duty and character of the circuit with which my circuit breaker is usable.

It is believed also evident from the foregoing, that the various features and objects of the invention are attained by the structure described, and that the breaker is comparatively small and compact in form and less expensive in construction than the usual circuit breakers of the same capacity utilizing insulating liquids such as hereinbefore referred to. It is also pointed out that various changes may be made in the form and structure of the parts without departing from the spirit and scope of the invention as set forth in the appended claims.

Having thus fully described my invention, its utility and mode of operation, what I claim and desire to secure by Letters Patent of the United States is- 1. In an electrical circuit breaker, an insulating housing having an airA filled chamber, a pair of main contact members in said chamber forming the terminals of a circuit to be interrupted, an intermediate contact member movably supported in the chamber between the two main contact members, means for moving one of the main Contact members from engagement with the intermediate contact member to thereby produce an arc and thereby provide gas under pressure within the housing, the other of the said main contact members mounted to permit movement by pressure of the arc gases generated within the housing and having a passageway to atmosphere normally closed by the intermediate contact member and opened by pressure developed by said arc produced gases whereby the gases under pressure are discharged to atmosphere between the co-acting surfaces of the intermediate and apertured contact member to thereby quench the arc therebetween.

2. In an electrical circuit breaker, an insulating housing, a pair of axially aligned main contact members therein forming the terminals of a circuit to be interrupted, an intermediate contact member, means normally supporting the intermediate contact member in axial alignment between the said main contact members, means for separating one of the main contact members from the intermediate contact member and the other of the main contact members being mounted to permit movement by pressure of the arc gases generated within the housing, there being an opening to atmosphere normally closed by the intermediate contact member and opened by movement of the said movable contact member under pressure of the gases whereby the coacting surfaces of the intermediate and last named main Contact member are swept by the gases in passage through the opening to atmosphere.

3. Inan electric circuit breaker, a housing of insulating material having a chamber extending longitudinally thereof, a pair of main contact elements forming terminals of a circuit to be interrupted, an intermediate contact member p0- sitioned in the arc path between the said contact elements, means for moving one of the main contacts from engagement with the intermediate member to thereby draw an arc and produce high pressure gases in the chamber, the other main contact having an aperture therethrough to atmosphere normally closed by the intermediate member, a spring normally tending to force the apertured main contact member to engagement with the intermediate member, the arrangement providing that pressure developed by the gases separates the intermediate and the apertured contact members, whereby the co-acting surfaces of the two said members are swept by the gases in passing to atmosphere through the said apertured contact member.

4. A circuit breaker comprising an insulating, air lled, housing, a plurality of contact members enclosed therewithin, means for operating the members in such manner that at least two of the members are separated whereby an arc is drawn therebetween generating a high pressure gas within the housing, another of said contact members being mounted to permit movement whereby the generated gases tend to separate the remaining engaged contact members, said housing being opened to a flow of gases therefrom by separation of the said last named contact members whereby the co-acting surfaces thereof are swept by the said gases and the arc extinguished.

5. A circuit breaker comprising a housing having a central bore and a counter-bore of greater diameter opening through one end, a main contact member movably supported in the said bore, a second movable main contact member, a cap member having an aperture through which the said member extends and is slidable, a anged sleeve secured in place with the ange thereof between the cap and the end of the housing and with the cylindrical portion extending into the counter-bore, said second main contact having an aperture therethrough and an enlarged end portion riding approximately in contact with the inner wall of the sleeve, a spring between the said terminal end of thesaid second contact and the cap tending to move the said contact member inwardly of the recess, an intermediate member loosely mounted in the bottom of the said counter-bore and having a flange seating on the Wall at the bottom of the counter-bore and having a cone Shaped end engaging the inner end of the last named main contact to close the aperture therein and a coned portion on the opposite side of the ange for engagement with a coned face provided on the rst contact member, the said flange of the intermediate member being movable between the end of the sleeve and the said bottom of the counter-bore under influence of pressure of gases generated on movement of the rst named main contact, the end of the sleeve having notches therein permitting gases generated by the initial arc to pass through the slots and exert separating pressure between the intermediate electrode and the second main contact thereby separating the contacts and permitting flow of the gases between the co-acting surfaces of the said intermediate and apertured contact member to quench the arc.

6. A circuit breaker comprising an insulating housing, a movable main contact member and a second main contact member extending through the housing wall and having an aperture therethrough, an intermediate contact member having a central portion with a periphery in close relation with the inside wall ci the housing thereby providing a restricted, substantially cylindrical passageway between the said main contact members within the housing, the said central portion having a contiguous cone-shaped end normally closing the said apertured main contact member, means for separating the contact members in such a manner that arc gases are rst produced between the said movable and intermediate contact members whereby, upon subsequent separation of the said intermediate and apertured contact members, the said arc gases are forced to pass through the said restricted passageway thereby being guided concentrically and intimately over the entire surface of the said contiguous cone-shaped end of the intermediate contact member and subsequently axially through the entire length of the arc drawn between the said intermediate and apertured contact members.

'7. In an air circuit breaker, a housing, a separable contact structure formed of several members therewithin, one of the contact members extending through the housing wall and having an aperture therethrough, a second contact member having a portion in peripherally close association with the inside wall of the housing thereby providing a restricted passageway, the said portion of the second member having a contiguous contact end normally closing the aperture in the first named contact member whereby, upon separation, the arc gases produced between the other members of the contact structure are forced to pass through the said restricted passageway thereby being cooled and cleaned and subsequently guided concentrically and intimately over the entire surface of the said contiguous contact end and axially through the entire length of the arc drawn between the said second contact member and the contact member L having the aperture.

8. In an air circuit breaker, a housing having an opening, a separable contact structure within the housing comprising more than two contact members, an intermediate member of the said contact structure having a central portion in peripherally close association with the inside wall of the housing thereby providing a restricted passageway, the said central portion having a contiguous Contact portion, the arrangement providing that, upon separation of the contact structures, the arc gases produced in the housing are caused to pass through the restricted passageway thereby being cooled, cleaned, and guided to sweep concentrically about and in contact with the entire surface of the said contiguous contact portion and subsequently pass axially `through the length of the drawn arc to said opening of the housing.

OLAV MASENG. 

